IUCN threat status:

Habitat

Habitat and Ecology

Habitat and Ecology

This coastal species is usually found over the continental shelf and slope (Jefferson et al. 1993; Aguayo et al. 1998). The distribution of dusky dolphins along the west coast of South Africa and both coasts of South America is associated with the continental shelves and cool waters of the Benguela, Humboldt and Falkland Currents. Around New Zealand, these dolphins are associated mainly with various cold water currents (Brownell and Cipriano 1999). Van Waerebeek et al. (1995) suggested that dusky dolphins may be limited to water shallower than 200 m. Off Argentina, dusky dolphins have been sighted from the coast to almost 200 nautical miles offshore, but the present information does not allow us to conclude whether this species' distribution tends to be more coastal than offshore or vice versa due to the bias in coastal effort (Crespo et al. 1997). They seem to prefer waters with sea surface temperatures between 10C and 18C (Brownell and Cipriano 1999). Inshore/offshore shifts in abundance have been noted for Argentina and New Zealand. They do move over deep waters in some areas (e.g., New Zealand), but always along continental slopes.

Dusky dolphins take a wide variety of prey, including southern anchovy near the surface in shallower waters, as well as midwater and benthic prey, such as squid, hake, and lanternfishes. They may also engage in nocturnal feeding, in association with the deep scattering layer. New Zealand dolphins appear to engage in feeding deeper in the water column than do those from Argentine waters (Cipriano 1992; Wrsig et al. 1997).